Penn Study Finds Dopamine Replacement Therapy Associated with Increase in Impulse Control Disorders Among Early Parkinson's Disease Patients

New Penn Medicine research shows that neuropsychiatric symptoms such as depression, anxiety and fatigue are more common in newly diagnosed Parkinson’s disease (PD) patients compared to the general population. The study also found that initiation of dopamine replacement therapy, the most common treatment for PD, was associated with increasing frequency of impulse control disorders and excessive daytime sleepiness. The new findings, the first longitudinal study to come out of the Parkinson's Progression Markers Initiative (PPMI), are published in the August 15, 2014, issue of Neurology®, the medical journal of the American Academy of Neurology.

The PPMI, a landmark, multicenter observational clinical study sponsored by The Michael J. Fox Foundation for Parkinson’s Research, uses a combination of advanced imaging, biologics sampling and behavioral assessments to identify biomarkers of Parkinson’s disease progression. The Penn study, which represents neuropsychiatric and cognitive data from baseline through the first 24 months of follow up, was conducted in collaboration with the Philadelphia VA Medical Center and the University Hospital Donostia in Spain.

The study examined 423 newly diagnosed, untreated Parkinson’s patients and 196 healthy controls at baseline and 281 people with PD at six months. Of these, 261 PD patients and 145 healthy controls were evaluated at 12 months, and 96 PD patients and 83 healthy controls evaluated at 24 months.

PD patients were permitted to begin dopamine therapy at any point after their baseline evaluation.

“We hypothesized that neuropsychiatric symptoms would be common and stable in severity soon after diagnosis and that the initiation of dopamine replacement therapy would modify their natural progression in some way,” says senior author, Daniel Weintraub, MD, associate professor of Psychiatry and Neurology at the Perelman School of Medicine at the University of Pennsylvania and a fellow in Penn’s Institute on Aging.

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